Abstract; Background: The health consequences of weight ranges across low to
moderate and high levels of cardiorespiratory fitness are unknown.

Objective: To evaluate the validity of the 1995 US weight guidelines, while
considering cardiorespiratory fitness.

Methods: We followed 21,856 men, aged 30-83 y, who had a complete preventive
medical examination, including a maximal treadmill exercise test and body
composition assessment. There were 427 deaths (144 cardiovascular disease
(CVD); 143 cancer; 140 others) during an average of 8.1 y of follow-up. We
used Cox proportional hazards regression to examine the relations among
cardiorespiratory fitness, body mass index (BMI, kg/m^2), and all-cause and
CVD mortality.

Results: After adjustment for age, examination year, cigarette smoking and
alcohol intake, we observed that men with a BMI of 19.0 to < 25.0 and who
were unfit had 2.3 times the risk of all-cause mortality (95% confidence
interval (95% CI), 1.59-3.17, P < 0.001) compared with fit men in this BMI
group (reference category). Unfit men with a BMI of 25.0 to < 27.8 also had
a greater risk of all-cause mortality than fit men in the same BMI category.
Fit but overweight men (BMI > or = 27.8) had a similar rate of all-cause
mortality as physically fit men of normal weight (BMI 19.0 to < 25.0) and
had a lower risk of all-cause mortality than unfit and normal weight men.
Fit men of normal weight had the lowest CVD mortality, while unfit and
overweight men experienced the highest CVD mortality. Unfit men had
substantially higher CVD mortality than fit men in each BMI group.

Conclusions: Unfit men had higher all-cause and CVD mortality than fit men.
The health benefits of normal weights appear to be limited to men who have
moderate or high levels of cardiorespiratory fitness. These data suggest
that the 1995 US weight guidelines may be misleading unless
cardiorespiratory fitness is taken into account.